This research project proposes to confirm and to extend previous work by the authors which indicates that alterations in environmental trace metals affect both incidence and severity of experimental allergic encephalomyelitis (EAE) in SJL mice. Preliminary data are reviewed which suggest that mice fed a diet containing 600 ppm zinc as sulfate may develop EAE of greater severity than do animals ted a control diet containing 30 ppm zinc. Other preliminary data suggest that mice fed a diet containing 600 ppm nickel as sulfate may be relatively protected against clinical development of EAE in this model. An attempt will be made to replicate these findings over the three-year course of this study using larger numbers of SWXJ animals. In addition, syngeneic mixed lymphocyte reactions and mitogen assays will be conducted with lymphocytes from subsets of animals fed specific diets in order to begin the process of understanding altered immunologic mechanisms which may be induced under these conditions.